Our sterilized mushroom growing substrate uses a blend of organic coconut coir, vermiculite, compost, and calcium sulfate in a filter patch bag for optimal mushroom growth. Plus, the bag and packaging the mushroom growing substrate is sterilized in is fully compostable!

Use the directions below to make a mushroom growing tub easily at home.

  1. Before opening the Sterilized Substrate bag, prepare your fruiting chamber or mono-tub by thoroughly cleaning it with isopropyl alcohol. Be sure to wear latex gloves and do your best to keep your work area as sterile as possible.
    *If you need help setting up a fruiting chamber or mono-tub, please see the online guides available, so you know you are using the product correctly.
  2. Prior to opening the bag, be sure to break up the contents of the bag, so it can become aerated. Now, open the bag and dump the contents into your sterilized bin.
  3. Be sure you are still wearing gloves! Take a handful of the substrate in your hand and squeeze it. You should see a few drops of water come out as you squeeze. If you do not, begin to mix small amounts of sterilized water into the mix until it is at proper hydration.
    *Mushrooms exhale carbon dioxide and inhale oxygen. They will suffocate if there isn’t enough airflow available! Be sure your bin has proper airflow!**Sterilized Water: Water that is free of bacterial and/or microbial life. This is typically done using an autoclave or a pressure cooker. Additionally, you may choose to use 2-3 Tbsp. of hydrogen peroxide per gallon of water to sterilize it.
  4. You should use 3 lbs. of inoculated grain spawn per 7.5 lb. bag of the substrate. Mix your grain spawn thoroughly into the substrate in your tub. Still wearing latex gloves, cover your bin with its lid, but ensure there are filtered holes in it for air exchange.
    *Incubation for most species will take about 2-3 weeks; some longer. Check your bin regularly and look for healthy mycelium growth. Your bin will slowly turn white from mycelium growth.
  5. When the bin is fully colonized, you will begin to see mushroom pins or hyphae growing from the top of the substrate. At this point, you can either let the mushrooms continue to grow on their own or add a thin layer of coco coir or other media to the top.
    *Keep your bin humid, the air flowing, and you’ll be enjoying your own fungi right at home in no time.

Get a complete step-by-step guide to growing indoor mushrooms here.

Looking to grow mushrooms outdoors? You can use our mushroom substrate bags to grow mushrooms on outdoor beds with ease!

*Shall be used only for lawful purposes

4 reviews for Sterilized Mushroom Growing Substrate (7.5lb)

  1. Kim R Blackburn (verified owner)

    Again, never any contamination, comes in at the proper moisture content and they’re constantly striving to improve their products.

  2. Eric G. (verified owner)

    Great stuff! Works as advertised. Excellent substrate!

  3. Natalie Dennis (verified owner)

    Absolutely happy

  4. Anonymous (verified owner)

    Haven’t had the chance to use it yet.

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